1. Field of the Invention
The present invention relates to a tooth clamp, and more particularly to a tooth clamp for use with a rubber dam upon treatment of the root canal of a tooth.
2. Description of the Prior Art
When treating the root canal of a tooth as by extracting an exposed nerve in the central cavity formed in a decayed molar tooth or remedying such a decayed molar tooth, it is known to use a rubber dam sheet in surrounding relation to the decayed tooth for preventing a medicine from entering the oral cavity.
FIGS. 3 and 4 of the accompanying drawings illustrate a conventional process of using such a rubber dam sheet. The rubber dam sheet 11 has a central hole 11a smaller than the outer profile of a decayed tooth 12 to be treated. A clamp 13 has a pair of gripping plates 14, 14 having respective arcuate tooth contacts or grippers 14a, 14a defining a tooth gripping space P', the gripping plates 14, 14 also having spreading holes 14b, 14b respectively. The clamp 13 also includes a resilient arcuate bridge 15 interconnecting the gripping plates 14, 14. When attaching the rubber dam sheet 11 and the clamp 13 to the decayed tooth 12, the gripping plates 14, 14 are placed over the rubber dam sheet 11 so that the tooth gripping space P' is in vertical registry with the hole 11a in the rubber dam sheet 11. Then, the pointed tip ends of rubber dam forceps (not shown) are inserted respectively in the spreading holes 14b, 14b. While spreading the gripping plates 14, 14 apart with the rubber dam forceps to enlarge the tooth gripping space P' against the resiliency of the arcuate bridge 15, the rubber dam sheet 11 and the gripping plates 14, 14 are fitted over the tooth 12 in surrounding relation thereto. By spreading the gripping plates 14, 14 with the rubber dam forceps to enlarge the tooth gripping space P', the hole 11a in the rubber dam sheet 11 is also enlarged. After the rubber dam sheet 11 and the clamp 13 have been mounted on the tooth 12, the rubber dam forceps are removed to allow the hole 11a to shrink into intimately fitting relation to the cirfumerential surface of the neck of the decayed tooth 12.
Then, the outer periphery of the rubber sheet 11 is kept taut by a rubber dam holder 16. The clamp 13 serves as a tool for preventing the rubber dam sheet 11 from being detached from the tooth 12.
Since the decayed tooth 12 is surrounded by the rubber dam sheet 11, any medicine applied to the tooth 12 is prevented by the rubber dam sheet 11 from flowing into the oral cavity. Therefore, the decayed tooth 12 can quickly be treated while protecting the patient from the danger of the medicine.
However, since the tooth 12 is progressively tapered toward its roots, the clamp 13 tends to move down toward the tooth roots under the resiliency of the bridge 15 and due to contact by the dentist's fingers during treatment. Therefore, the edges of the tooth grippers 14a, 14a are caused to bite into the gum 17.